Data Input and Output Functions in C Programming

Data Input and output functions in C:

The C programming language  supports many library functions which includes a number of input/output functions. These functions are used to transfer the information between the computer and device(user).

  Some basic input/output functions are: 

• scanf() and printf(): These two functions are used to transfer the single characters, strings and numerical values.

• getchar() and putchar(): These two functions are used to transfer single characters.

• gets() and puts(): is used to input and output strings.

1. How to use scanf and printf functions:

scanf() function is used to take input from user(keyboard).

printf() function is used to display output on the screen.

  Example Program:

#include<stdio.h>

void main()

{

      int num;// variable definition

       /*Display message and ask user to enter some number... using printf()*/

      printf("Enter the number:");

      /*Read the number entered by user... using scanf()*/

      scanf("%d",&num);

     /*Display the number with message...using printf() */

      printf("You entered number is:  %d",num);

}

In above program %d is used to scan the intiger value.

If value is char then we use %c.

If value is float then we use %f and so on...

Above program shows the following output:

2. How to use getchar and putchar functions in our program: 

getchar() function reads  a single character from the terminal and returns it as an intiger.

putchar() function is used to display these single character.

  Example program:

#include<stdio.h>

void main()

{

      int a;

      printf("Enter a character:");

      /*Here, getchar function is used to store the accepted character in variable a*/

     a = getchar();    

     /*Display the character stored in variable a using putchar function*/

     putchar(a);

}

Above program shows the following output:

3. How to use gets() and puts() function in C:

In simple words:

gets() function is used to accept string from user.

puts() function is used to display the string.

  Example program:

 

#include<stdio.h>

void main()

{

      //Declare character array to store string

      char str[100];

      printf("Enter a string: ");

       /*store string in array str*/

      gets(str);

      /*Display string on the output screen*/

      puts(str);

}

Above program shows the following output: